Electronic cards or integrated circuit cards have considerably developed over the last few years. Initially, electronic cards were formed of a card body including a resistive contact module housed in a recess in the body of the card. Then, contactless cards were made, i.e. cards including a transponder formed of an electronic circuit connected to an antenna. As electronic cards develop, it is sought to integrate other electronic elements for other functions into the cards. By way of example, cards including a switch that can be activated by the user and an electronic display have been disclosed. Such cards generally require relatively large batteries or powering means of the photovoltaic cell type. In order to integrate these various elements in a card, they are generally grouped together in the form of at least one electronic module, including a support or substrate, on the surface of which various electronic elements are arranged. FIG. 1 shows a schematic example of this type of module. Module 2 includes an integrated circuit 4, connected to an electronic display 6, a battery 8 and an activator 10, arranged on a support 12, forming a PCB interconnecting these various elements. In order to limit the thickness of these modules, the battery and/or the display can be arranged at the periphery of support 12 or in recesses therein.
It is not easy to integrate a relatively large electronic module, made up of various elements of variable shape and size, in a card. Further, integrating a digital display, which has to be precisely positioned in the manufactured card, causes an additional problem, which the present invention proposes to overcome.
EP Patent No. 0 570 784 discloses, in one implementation, a method of manufacturing cards including an electronic assembly, in particular, a transponder, which is placed in a main aperture of a positioning frame. According to the implementation disclosed, the transponder and the positioning frame are embedded in a binding agent that can be added in viscous liquid form, particularly a resin. In EP Patent No. 0 570 784, the positioning frame is only used for delimiting an inner zone for the transponder, formed of an integrated circuit and a coil, inside the card. Thus, when pressure is applied to the various elements and the binding agent to form a card, the transponder is held in an inner zone, whereas it is possible for the binding agent, in a non-solid state, to spread out on to form a layer that passes through the manufactured card. Those skilled in the art can find, in this Patent document, a method for integrating a relatively large and complex-shaped electronic module in a compact, flat card. However, the electronic module placed in the main aperture of a positioning frame, as described in that document, will often be moved slightly when the card is being formed. Indeed, this document does not disclose how to maintain the transponder in a precise, determined position inside the aperture of the positioning frame. Those skilled in the art might certainly think of reducing the dimensions of the main aperture to make them approximately match the dimensions of the electronic module, in particular the external profile of the module. However, manufacturing tolerances must be taken into account, so that it is difficult to envisage too tight a fit. Moreover, depending upon the way in which the modules are manufactured, the positioning of the various elements on the support may also vary slightly. Thus, for example, digital display 6 is arranged on the surface of the PCB or at the periphery thereof in a position that may vary slightly. However, to obtain a high quality card, this digital display must be positioned precisely relative to the external contour of the manufactured card. This is particular important when a transparent aperture, which fits the dimensions of the digital display, is arranged above the digital display to allow the user of the card to read the display.
There is a further problem in addition to this problem of positioning the electronic module relative to the external contour of the card. This problem concerns introducing the electronic module within the card manufacturing installation. It will be noted here that electronic cards are generally manufactured in batches, i.e. several cards are manufactured simultaneously in the form of a plate that includes a plurality of electronic modules. Then, each card is separated from the obtained plate during a cutting step, as is described in EP Patent No. 0 570 784. Within the scope of the embodiments described in the latter disclosure, the transponder remains free in relation to the positioning frame until the card is formed. This requires precautions in the handling of the various elements brought to form the card, to ensure that the transponders remain in the corresponding apertures in the positioning structure until the press is activated.
The present invention thus also proposes to answer this latter problem, in order to simplify the provision of electronic modules, while ensuring that the electronic modules are held in the apertures of a positioning structure and to facilitate assembly of the various elements and materials provided for manufacturing the cards.
Therefore, the present invention concerns, firstly, an assembly produced during the manufacture of cards, which each include an electronic module. The card manufacturing process includes the provision of a plate, which has at least one, at least partially through aperture, and at least one electronic module, which is electrically independent of said plate and housed, at least partially, in said at least one aperture, in an installation where a resin is added to at least one side of said electronic module, said plate forming a positioning structure for said electronic module. This assembly includes said plate and said at least one electronic module and is characterized in that, before said assembly is brought to said installation, said plate and said at least one electronic module are assembled in a sufficiently rigid manner for said at least one electronic module to remain in a substantially defined position relative to said plate, firstly until the resin is added, and subsequently during said resin is added.
It should be noted that the resin could be added in various forms and in various states. The term “resin” should be understood in a broad sense, including various known adhesives, PVC and Polyurethane resins or other resins available to those skilled in the art.
In a preferred embodiment, each aperture and/or the electronic module located in said aperture are arranged such that a space remains in the aperture, and open on at least one side of the plate. The card or intermediate product manufacturing process then includes a step where a filling material is introduced into this space remaining in the apertures.
Assembling the plate pierced with apertures and electronic modules in a preliminary step of the card manufacturing method has numerous advantages and answers the aforementioned problem. The fact that a material connection is made between the electronic module and the plate means that the assembly can be handled, in particular, via the plate, in order to implement subsequent steps in the card manufacturing method. The assembly according to the invention resolves the problem of holding the electronic modules in the apertures of the plate, when the plate and electronic modules are brought into an installation where a resin is added in accordance with the card or intermediate product manufacturing method of the invention.
In the preferred embodiment, wherein a space remains in the apertures of the pierced plate after the assembly according to the invention has been assembled, the spaces remaining in the apertures are generally filled with a filling material or a resin by applying pressure, particular using a press or a roller that spreads out the filling material or resin. If no particular precautions are taken, this step may move the electronic modules relative to the frame. The assembly according to the present invention resolves this problem in an advantageous manner, by maintaining the modules in a precise position during the entire card manufacturing method; both in the general plane of the plate and along the axis perpendicular to the general plane.
The present invention also concerns an intermediate product of the card manufacturing process, which comprises an assembly according to the aforementioned preferred embodiment, and a filling material, which fills at least most of the space remaining in the plate apertures where the electronic modules are situated. The top and bottom surfaces of this intermediate product are preferably more or less flat. In a first variant, the thickness of the intermediate product is approximately the same as said plate, the filling material being essentially provided in the spaces remaining in the plate apertures. In a second variant, the filling material is formed by a resin, which covers at least one of the top and bottom surfaces of the plate. In this latter case, the intermediate product has improved rigidity, because the resin covers at least one side of the plate and preferably both sides.
If the resin covers both sides of the plate and the electronic modules, the intermediate product can already be used as a card, when the outer surfaces are approximately flat. However, there are several advantages to making the intermediate product according to the invention in a card manufacturing method that includes at least one further step of adding resin to both sides of the intermediate product. The present invention also concerns this manufacturing method. According to this method of manufacturing at least one card, an intermediate product, as defined above, is made, and then the resin is deposited on at least one of the top and bottom surfaces of the intermediate product. Finally, pressure is applied to the deposited resin, which is then in a non-solid state, to form at least one card that has a flat outer surface, since the resin deposited on the intermediate product fills in any variations in thickness in the intermediate product. The resin deposited on the intermediate product preferably forms a thin layer. The resin can be added in a single step or in several successive steps to further improve flatness.
This method is particularly advantageous for obtaining cards which have a perfectly flat surface and which incorporate a relatively large electronic module that has variations in thickness and is formed of various elements. In fact, when the electronic module is formed of various elements, made of different materials and with different levels of thickness and empty intermediate zones, the filling material or resin added to the remaining space in the plate aperture is distributed in an irregular manner, with variations in thickness. When the filling material or resin hardens, shrinkage, and thus a variation in thickness, may occur in the resin, which then generates a surface with slight hollows or bumps. The surface state of the intermediate product generally does not meet the bankcard standards, but the variations in thickness can be removed, by subsequently depositing a resin film on both sides of the intermediate product, when the finished cards are formed. The cards then have perfectly flat outer surfaces.